Laser mask and method of crystallization using the same

Abstract

A laser mask and method of crystallization using the same that can produce a polycrystalline silicon thin film having uniform crystallization characteristics. According to the present invention, a method of crystallization using a laser mask having a reference pattern in a first block and the reverse pattern of the reference pattern in a second block includes providing a substrate having a silicon thin film; positioning the first block of the laser mask over a portion of the silicon film and irradiating a first laser beam through the first block; and moving either the laser mask or the substrate to position the second block of the laser mask over the portion of the silicon film and irradiating a second laser beam through the second block.

1. A laser mask having first and second blocks comprising:
 a reference pattern in the first block; and 
 the reverse pattern of the reference pattern in the second block. 
 
     
     
       2. The laser mask of  claim 1 , wherein the reference pattern includes a plurality of first transmitting regions and a first blocking region, and the reverse pattern includes a plurality of second blocking regions and a second transmitting region. 
     
     
       3. The laser mask of  claim 2 , wherein the first transmitting regions and the second blocking regions have the same shape and the first blocking region and the second transmitting region have the same shape. 
     
     
       4. The laser mask of  claim 2 , wherein the first transmitting regions and the second blocking regions are formed in a round shape. 
     
     
       5. The laser mask of  claim 4 , wherein a radius of the first transmitting regions is equal to or less than a half of the distance between the centers of the two adjacent first transmitting regions. 
     
     
       6. The laser mask of  claim 2 , wherein the centers of the adjacent first transmitting regions form a regular polygon shape the regular polygon shape including a regular triangle, a regular square, a regular hexagon and a regular octagon. 
     
     
       7. The laser mask of  claim 1 , wherein the reference pattern has a periodicity or regularity. 
     
     
       8. The laser mask of  claim 2 , wherein the first transmitting regions are randomly or irregularly distributed in the first block. 
     
     
       9. A method of crystallization using a laser mask having a reference pattern in a first block and the reverse pattern of the reference pattern in a second block, comprising:
 (a) providing a substrate having a silicon thin film; 
 (b) positioning the first block of the laser mask over a portion of the silicon film and irradiating a first laser beam through the first block; and 
 (c) moving either the laser mask or the substrate to position the second block of the laser mask over the portion of the silicon film and irradiating a second laser beam through the second block. 
 
     
     
       10. The method of  claim 9 , wherein the reference pattern includes a plurality of first transmitting regions and a first blocking region, and the reverse pattern includes a plurality of second blocking regions and a second transmitting region. 
     
     
       11. The method of  claim 10 , wherein the first transmitting regions and the second blocking regions have the same shape and the first blocking region and the second transmitting region have the same shape. 
     
     
       12. The method of  claim 10 , wherein the first transmitting regions and the second blocking regions are formed in a round shape. 
     
     
       13. The method of  claim 12 , wherein a radius of the first transmitting regions is equal to or less than a half of the distance between the centers of the two adjacent first transmitting regions. 
     
     
       14. The method of  claim 10 , the centers of the adjacent first transmitting regions form a regular polygon shape, the regular polygon shape including a regular triangle, a regular square, a regular hexagon and a regular octagon. 
     
     
       15. The method of  claim 10 , wherein all the first transmittance regions have the same size. 
     
     
       16. The method of  claim 10 , wherein the first transmittance regions have different sizes. 
     
     
       17. The method of  claim 9 , wherein the reference pattern has a periodicity or regularity. 
     
     
       18. The method of  claim 10 , wherein the first transmitting regions are randomly or irregularly distributed in the first block. 
     
     
       19. The method of  claim 9 , wherein the first and second laser beam have an energy density of a complete melting region. 
     
     
       20. The method of  claim 9 , wherein the crystallization is a sequential lateral crystallization. 
     
     
       21. The method of  claim 10 , wherein the size of the first transmitting regions are determined in consideration of the energy density of the first and second laser beams and an alignment error that occurs during the movement. 
     
     
       22. The method of  claim 9 , further comprising: repeating (b) and (c) steps in an X-axis direction; moving either the laser mask or the substrate in a Y-axis direction; and repeating (b) and (c) steps in a minus X-axis direction. 
     
     
       23. The laser mask of  claim 1 , wherein the reference pattern is in contact with the reverse pattern in the laser mask.